The present invention relates to an apparatus for treating a silver halide photographic light-sensitive material, in which electrodes are provided in a developing tank and in which the treating ability of a developing solution can be recovered through applying a current to the developing solution between the electrodes.
For example, wet treatment for a silver halide monochrome photographic light-sensitive material is carried out by treatment processes such as developing, fixing, washing, and the like. If necessary, processes such as washing and the like may be effected between the respective processes. A developing solution and a fixing solution are used in these developing and fixing processes, respectively. As the light-sensitive material is treated, a developing agent contained in the developing solution is oxidized so that the developing solution becomes tired and halogen ions are accumulated in the developing solution. Furthermore, silver ions and halogen ions are accumulated in the fixing solution due to the fixing operation. As a result, the treating abilities of those solutions are lowered. Therefore, supplementary solutions, each containing necessary components similar to those of a corresponding treatment solution, are respectively supplied to the treatment solutions so -that the treating abilities of the treatment solutions can be maintained.
If supplementary solutions are supplied to the respective treatment solutions so that the treating abilities of the treatment solutions are not lowered, however, overflow liquid of a quantity substantially equal to the quantity of the supplied liquid is discharged as waste fluid. The waste fluid is discarded, eventually reaching the sea, resulting in global environmental pollution.
In recent years, however, discharge of photographic treatment waste fluid into the sea has been reconsidered in light of the growing consensus that the global environment must be protected. Although a method of destroying photographic treatment waste fluid by incineration may be proposed instead of discharge into the sea, the method results in another type of global environmental pollution problem due to the discharge of carbon dioxide. Accordingly, techniques for rendering waste fluid harmless and techniques for reducing the quantity of waste fluid have been desired to replace the conventional methods.
Examples of techniques for rendering photographic waste fluids harmless include an activated-sludge process employing a biological treatment, wet oxidation process, and the like. These processes, however, require large-scale treatment apparatuses, so that it is necessary to collect waste fluid and apply batch integrated treatment to the collected waste fluid. As examples of techniques for reducing the quantity of waste fluid, a low supplement system, an on-site liquid regeneration system (apparatus in which an automatic developing apparatus and a treatment solution regeneration apparatus are integrated into one unit), an on-site waste fluid treatment system (apparatus in which an automatic developing apparatus and a waste fluid treatment apparatus are integrated into a single unit), and the like, are known. These are, however, techniques effective only for large-scale treatment laboratories.
On the other hand, with the advance of technology, photographic treatment is carried out not only at the level of large- to small-scale laboratories, but also in the so-called "mini-" and "micro-scale" laboratory level. Particularly at the mini-scale laboratory level and in the micro-scale laboratory level, the problem on waste fluid has been exacerbated since photographic treatment at many different locations. That is, at tile mini-scale laboratory level it is quite difficult to treat waste fluid with an apparatus united with the automatic developing apparatus. Also, the costs for collecting the waste fluid are high, and it is substantially difficult to collect the waste fluid.
Significant reduction of the amount of waste fluid discharged can be attained if the quantity of supplementary solution is extremely reduced. In such a case, however, it is necessary to recover the treating ability by other means. For example, in the case of a developing solution, recovering the ability of the treatment solution is synonymous with reducing a developing agent oxidized by developing treatment. This reduction must be accomplished by means other than addition of a supplementary solution.
In the case where a chelate metal compound is used as a developing agent in the development of a light-sensitive material, the chelate metal compound is oxidized by reduction of silver halide in the light-sensitive material so that chelate metal ions turn to higher-valency ions. That is, by subjecting the chelate metal ions to development, the valence of the ions increases. For example, in the case where chelate Fe(II) is used as the chelate metal compound, chelate Fe.sup.2+ turns to chelate Fe.sup.3+ with the advance of the developing treatment, so that the relative proportion of chelate Fe.sup.3+ increases.
The developing ability of the developing solution in a state where chelate Fe.sup.3+ has increased can be recovered by returning the chelate Fe.sup.3+ to chelate Fe.sup.2+. For example, chelate Fe.sup.3+ can be returned to chelate Fe.sup.2+ by giving electrons to chelate Fe.sup.3+. Therefore, it may be considered to employ a known electrolysis apparatus for applying a current to a liquid to perform oxidation or reduction for regeneration of a developing solution. Examples of such an approach are described in Japanese Patent Unexamined Publications Nos. Hei-3273237, Hei-3-209471 and Hei-3-293661.
However, in the case where a tired developing solution in the developing tank is to be recovered using an electrolysis apparatus, not only is work such as transferring the developing solution to the electrolysis apparatus troublesome, but the structure of equipment required for directly transferring the developing solution from the developing apparatus to the electrolysis apparatus is large in size because of the required pipes, circulatory pumps, filters and the like.